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Comparing jsr166/src/main/java/util/ArrayList.java (file contents):
Revision 1.12 by jsr166, Mon Nov 28 04:06:29 2005 UTC vs.
Revision 1.36 by jsr166, Mon Oct 31 23:02:42 2016 UTC

#	Line 1 | Line 1
1		/*
2	<	* %W% %E%
2	>	* Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3	>	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4		*
5	<	* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
6	<	* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
5	>	* This code is free software; you can redistribute it and/or modify it
6	>	* under the terms of the GNU General Public License version 2 only, as
7	>	* published by the Free Software Foundation.  Oracle designates this
8	>	* particular file as subject to the "Classpath" exception as provided
9	>	* by Oracle in the LICENSE file that accompanied this code.
10	>	*
11	>	* This code is distributed in the hope that it will be useful, but WITHOUT
12	>	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13	>	* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14	>	* version 2 for more details (a copy is included in the LICENSE file that
15	>	* accompanied this code).
16	>	*
17	>	* You should have received a copy of the GNU General Public License version
18	>	* 2 along with this work; if not, write to the Free Software Foundation,
19	>	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20	>	*
21	>	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22	>	* or visit www.oracle.com if you need additional information or have any
23	>	* questions.
24		*/
25
26		package java.util;
27	<	import java.util.*; // for javadoc (till 6280605 is fixed)
27	>
28	>	import java.util.function.Consumer;
29	>	import java.util.function.Predicate;
30	>	import java.util.function.UnaryOperator;
31
32		/**
33	<	* Resizable-array implementation of the <tt>List</tt> interface.  Implements
33	>	* Resizable-array implementation of the {@code List} interface.  Implements
34		* all optional list operations, and permits all elements, including
35	<	* <tt>null</tt>.  In addition to implementing the <tt>List</tt> interface,
35	>	* {@code null}.  In addition to implementing the {@code List} interface,
36		* this class provides methods to manipulate the size of the array that is
37		* used internally to store the list.  (This class is roughly equivalent to
38	<	* <tt>Vector</tt>, except that it is unsynchronized.)<p>
38	>	* {@code Vector}, except that it is unsynchronized.)
39		*
40	<	* The <tt>size</tt>, <tt>isEmpty</tt>, <tt>get</tt>, <tt>set</tt>,
41	<	* <tt>iterator</tt>, and <tt>listIterator</tt> operations run in constant
42	<	* time.  The <tt>add</tt> operation runs in <i>amortized constant time</i>,
40	>	* <p>The {@code size}, {@code isEmpty}, {@code get}, {@code set},
41	>	* {@code iterator}, and {@code listIterator} operations run in constant
42	>	* time.  The {@code add} operation runs in <i>amortized constant time</i>,
43		* that is, adding n elements requires O(n) time.  All of the other operations
44		* run in linear time (roughly speaking).  The constant factor is low compared
45	<	* to that for the <tt>LinkedList</tt> implementation.<p>
45	>	* to that for the {@code LinkedList} implementation.
46		*
47	<	* Each <tt>ArrayList</tt> instance has a <i>capacity</i>.  The capacity is
47	>	* <p>Each {@code ArrayList} instance has a <i>capacity</i>.  The capacity is
48		* the size of the array used to store the elements in the list.  It is always
49		* at least as large as the list size.  As elements are added to an ArrayList,
50		* its capacity grows automatically.  The details of the growth policy are not
51		* specified beyond the fact that adding an element has constant amortized
52	<	* time cost.<p>
52	>	* time cost.
53		*
54	<	* An application can increase the capacity of an <tt>ArrayList</tt> instance
55	<	* before adding a large number of elements using the <tt>ensureCapacity</tt>
54	>	* <p>An application can increase the capacity of an {@code ArrayList} instance
55	>	* before adding a large number of elements using the {@code ensureCapacity}
56		* operation.  This may reduce the amount of incremental reallocation.
57		*
58		* <p><strong>Note that this implementation is not synchronized.</strong>
59	<	* If multiple threads access an <tt>ArrayList</tt> instance concurrently,
59	>	* If multiple threads access an {@code ArrayList} instance concurrently,
60		* and at least one of the threads modifies the list structurally, it
61		* <i>must</i> be synchronized externally.  (A structural modification is
62		* any operation that adds or deletes one or more elements, or explicitly
#	Line 49 | Line 70 | import java.util.*; // for javadoc (till
70		* unsynchronized access to the list:<pre>
71		*   List list = Collections.synchronizedList(new ArrayList(...));</pre>
72		*
73	<	* <p>The iterators returned by this class's <tt>iterator</tt> and
74	<	* <tt>listIterator</tt> methods are <i>fail-fast</i>: if the list is
75	<	* structurally modified at any time after the iterator is created, in any way
76	<	* except through the iterator's own <tt>remove</tt> or <tt>add</tt> methods,
77	<	* the iterator will throw a {@link ConcurrentModificationException}.  Thus, in
78	<	* the face of concurrent modification, the iterator fails quickly and cleanly,
79	<	* rather than risking arbitrary, non-deterministic behavior at an undetermined
80	<	* time in the future.<p>
73	>	* <p id="fail-fast">
74	>	* The iterators returned by this class's {@link #iterator() iterator} and
75	>	* {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>:
76	>	* if the list is structurally modified at any time after the iterator is
77	>	* created, in any way except through the iterator's own
78	>	* {@link ListIterator#remove() remove} or
79	>	* {@link ListIterator#add(Object) add} methods, the iterator will throw a
80	>	* {@link ConcurrentModificationException}.  Thus, in the face of
81	>	* concurrent modification, the iterator fails quickly and cleanly, rather
82	>	* than risking arbitrary, non-deterministic behavior at an undetermined
83	>	* time in the future.
84		*
85	<	* Note that the fail-fast behavior of an iterator cannot be guaranteed
85	>	* <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
86		* as it is, generally speaking, impossible to make any hard guarantees in the
87		* presence of unsynchronized concurrent modification.  Fail-fast iterators
88	<	* throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
88	>	* throw {@code ConcurrentModificationException} on a best-effort basis.
89		* Therefore, it would be wrong to write a program that depended on this
90	<	* exception for its correctness: <i>the fail-fast behavior of iterators
91	<	* should be used only to detect bugs.</i><p>
90	>	* exception for its correctness:  <i>the fail-fast behavior of iterators
91	>	* should be used only to detect bugs.</i>
92		*
93	<	* This class is a member of the
94	<	* <a href="{@docRoot}/../guide/collections/index.html">
93	>	* <p>This class is a member of the
94	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
95		* Java Collections Framework</a>.
96		*
97	+	* @param <E> the type of elements in this list
98	+	*
99		* @author  Josh Bloch
100		* @author  Neal Gafter
101	<	* @version %I%, %G%
102	<	* @see     Collection
103	<	* @see     List
104	<	* @see     LinkedList
79	<	* @see     Vector
101	>	* @see     Collection
102	>	* @see     List
103	>	* @see     LinkedList
104	>	* @see     Vector
105		* @since   1.2
106		*/
82	–
107		public class ArrayList<E> extends AbstractList<E>
108		implements List<E>, RandomAccess, Cloneable, java.io.Serializable
109		{
110		private static final long serialVersionUID = 8683452581122892189L;
111
112		/**
113	+	* Default initial capacity.
114	+	*/
115	+	private static final int DEFAULT_CAPACITY = 10;
116	+
117	+	/**
118	+	* Shared empty array instance used for empty instances.
119	+	*/
120	+	private static final Object[] EMPTY_ELEMENTDATA = {};
121	+
122	+	/**
123	+	* Shared empty array instance used for default sized empty instances. We
124	+	* distinguish this from EMPTY_ELEMENTDATA to know how much to inflate when
125	+	* first element is added.
126	+	*/
127	+	private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {};
128	+
129	+	/**
130		* The array buffer into which the elements of the ArrayList are stored.
131	<	* The capacity of the ArrayList is the length of this array buffer.
131	>	* The capacity of the ArrayList is the length of this array buffer. Any
132	>	* empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA
133	>	* will be expanded to DEFAULT_CAPACITY when the first element is added.
134		*/
135	<	private transient Object[] elementData;
135	>	transient Object[] elementData; // non-private to simplify nested class access
136
137		/**
138		* The size of the ArrayList (the number of elements it contains).
#	Line 101 | Line 144 | public class ArrayList<E> extends Abstra
144		/**
145		* Constructs an empty list with the specified initial capacity.
146		*
147	<	* @param initialCapacity the initial capacity of the list
147	>	* @param  initialCapacity  the initial capacity of the list
148		* @throws IllegalArgumentException if the specified initial capacity
149		*         is negative
150		*/
151		public ArrayList(int initialCapacity) {
152	<	super();
153	<	if (initialCapacity < 0)
152	>	if (initialCapacity > 0) {
153	>	this.elementData = new Object[initialCapacity];
154	>	} else if (initialCapacity == 0) {
155	>	this.elementData = EMPTY_ELEMENTDATA;
156	>	} else {
157		throw new IllegalArgumentException("Illegal Capacity: "+
158		initialCapacity);
159	<	this.elementData = new Object[initialCapacity];
159	>	}
160		}
161
162		/**
163		* Constructs an empty list with an initial capacity of ten.
164		*/
165		public ArrayList() {
166	<	this(10);
166	>	this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA;
167		}
168
169		/**
170		* Constructs a list containing the elements of the specified
171		* collection, in the order they are returned by the collection's
172	<	* iterator.  The <tt>ArrayList</tt> instance has an initial capacity of
127	<	* 110% the size of the specified collection.
172	>	* iterator.
173		*
174		* @param c the collection whose elements are to be placed into this list
175		* @throws NullPointerException if the specified collection is null
176		*/
177		public ArrayList(Collection<? extends E> c) {
178	<	int size = c.size();
179	<	// 10% for growth
180	<	int cap = ((size/10)+1)*11;
181	<	if (cap > 0) {
182	<	Object[] a = new Object[cap];
183	<	a[size] = a[size+1] = UNALLOCATED;
184	<	Object[] b = c.toArray(a);
185	<	if (b[size] == null && b[size+1] == UNALLOCATED) {
186	<	b[size+1] = null;
187	<	elementData = b;
143	<	this.size = size;
144	<	return;
145	<	}
146	<	}
147	<	initFromConcurrentlyMutating(c);
148	<	}
149	<
150	<	private void initFromConcurrentlyMutating(Collection<? extends E> c) {
151	<	elementData = c.toArray();
152	<	size = elementData.length;
153	<	// c.toArray might (incorrectly) not return Object[] (see 6260652)
154	<	if (elementData.getClass() != Object[].class)
155	<	elementData = Arrays.copyOf(elementData, size, Object[].class);
178	>	elementData = c.toArray();
179	>	if ((size = elementData.length) != 0) {
180	>	// defend against c.toArray (incorrectly) not returning Object[]
181	>	// (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652)
182	>	if (elementData.getClass() != Object[].class)
183	>	elementData = Arrays.copyOf(elementData, size, Object[].class);
184	>	} else {
185	>	// replace with empty array.
186	>	this.elementData = EMPTY_ELEMENTDATA;
187	>	}
188		}
189
158	–	private final static Object UNALLOCATED = new Object();
159	–
190		/**
191	<	* Trims the capacity of this <tt>ArrayList</tt> instance to be the
191	>	* Trims the capacity of this {@code ArrayList} instance to be the
192		* list's current size.  An application can use this operation to minimize
193	<	* the storage of an <tt>ArrayList</tt> instance.
193	>	* the storage of an {@code ArrayList} instance.
194		*/
195		public void trimToSize() {
196	<	modCount++;
197	<	int oldCapacity = elementData.length;
198	<	if (size < oldCapacity) {
199	<	elementData = Arrays.copyOf(elementData, size);
200	<	}
196	>	modCount++;
197	>	if (size < elementData.length) {
198	>	elementData = (size == 0)
199	>	? EMPTY_ELEMENTDATA
200	>	: Arrays.copyOf(elementData, size);
201	>	}
202		}
203
204		/**
205	<	* Increases the capacity of this <tt>ArrayList</tt> instance, if
205	>	* Increases the capacity of this {@code ArrayList} instance, if
206		* necessary, to ensure that it can hold at least the number of elements
207		* specified by the minimum capacity argument.
208		*
209		* @param minCapacity the desired minimum capacity
210		*/
211		public void ensureCapacity(int minCapacity) {
212	<	modCount++;
213	<	if (minCapacity > elementData.length)
214	<	growArray(minCapacity);
212	>	if (minCapacity > elementData.length
213	>	&& !(elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA
214	>	&& minCapacity <= DEFAULT_CAPACITY)) {
215	>	modCount++;
216	>	grow(minCapacity);
217	>	}
218		}
219
220		/**
221	<	* Increases the capacity of the array.
221	>	* The maximum size of array to allocate (unless necessary).
222	>	* Some VMs reserve some header words in an array.
223	>	* Attempts to allocate larger arrays may result in
224	>	* OutOfMemoryError: Requested array size exceeds VM limit
225	>	*/
226	>	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
227	>
228	>	/**
229	>	* Increases the capacity to ensure that it can hold at least the
230	>	* number of elements specified by the minimum capacity argument.
231		*
232		* @param minCapacity the desired minimum capacity
233	+	* @throws OutOfMemoryError if minCapacity is less than zero
234		*/
235	<	private void growArray(int minCapacity) {
236	<	if (minCapacity < 0)
237	<	throw new OutOfMemoryError(); // int overflow
238	<	int oldCapacity = elementData.length;
239	<	// Double size if small; else grow by 50%
240	<	int newCapacity = ((oldCapacity < 64)?
241	<	((oldCapacity + 1) * 2):
242	<	((oldCapacity * 3) / 2));
243	<	if (newCapacity < minCapacity)
244	<	newCapacity = minCapacity;
245	<	elementData = Arrays.copyOf(elementData, newCapacity);
235	>	private Object[] grow(int minCapacity) {
236	>	return elementData = Arrays.copyOf(elementData,
237	>	newCapacity(minCapacity));
238	>	}
239	>
240	>	private Object[] grow() {
241	>	return grow(size + 1);
242	>	}
243	>
244	>	/**
245	>	* Returns a capacity at least as large as the given minimum capacity.
246	>	* Returns the current capacity increased by 50% if that suffices.
247	>	* Will not return a capacity greater than MAX_ARRAY_SIZE unless
248	>	* the given minimum capacity is greater than MAX_ARRAY_SIZE.
249	>	*
250	>	* @param minCapacity the desired minimum capacity
251	>	* @throws OutOfMemoryError if minCapacity is less than zero
252	>	*/
253	>	private int newCapacity(int minCapacity) {
254	>	// overflow-conscious code
255	>	int oldCapacity = elementData.length;
256	>	int newCapacity = oldCapacity + (oldCapacity >> 1);
257	>	if (newCapacity - minCapacity <= 0) {
258	>	if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA)
259	>	return Math.max(DEFAULT_CAPACITY, minCapacity);
260	>	if (minCapacity < 0) // overflow
261	>	throw new OutOfMemoryError();
262	>	return minCapacity;
263	>	}
264	>	return (newCapacity - MAX_ARRAY_SIZE <= 0)
265	>	? newCapacity
266	>	: hugeCapacity(minCapacity);
267	>	}
268	>
269	>	private static int hugeCapacity(int minCapacity) {
270	>	if (minCapacity < 0) // overflow
271	>	throw new OutOfMemoryError();
272	>	return (minCapacity > MAX_ARRAY_SIZE)
273	>	? Integer.MAX_VALUE
274	>	: MAX_ARRAY_SIZE;
275		}
276
277		/**
#	Line 207 | Line 280 | public class ArrayList<E> extends Abstra
280		* @return the number of elements in this list
281		*/
282		public int size() {
283	<	return size;
283	>	return size;
284		}
285
286		/**
287	<	* Returns <tt>true</tt> if this list contains no elements.
287	>	* Returns {@code true} if this list contains no elements.
288		*
289	<	* @return <tt>true</tt> if this list contains no elements
289	>	* @return {@code true} if this list contains no elements
290		*/
291		public boolean isEmpty() {
292	<	return size == 0;
292	>	return size == 0;
293		}
294
295		/**
296	<	* Returns <tt>true</tt> if this list contains the specified element.
297	<	* More formally, returns <tt>true</tt> if and only if this list contains
298	<	* at least one element <tt>e</tt> such that
299	<	* <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
296	>	* Returns {@code true} if this list contains the specified element.
297	>	* More formally, returns {@code true} if and only if this list contains
298	>	* at least one element {@code e} such that
299	>	* {@code Objects.equals(o, e)}.
300		*
301		* @param o element whose presence in this list is to be tested
302	<	* @return <tt>true</tt> if this list contains the specified element
302	>	* @return {@code true} if this list contains the specified element
303		*/
304		public boolean contains(Object o) {
305	<	return indexOf(o) >= 0;
305	>	return indexOf(o) >= 0;
306		}
307
308		/**
309		* Returns the index of the first occurrence of the specified element
310		* in this list, or -1 if this list does not contain the element.
311	<	* More formally, returns the lowest index <tt>i</tt> such that
312	<	* <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
311	>	* More formally, returns the lowest index {@code i} such that
312	>	* {@code Objects.equals(o, get(i))},
313		* or -1 if there is no such index.
314		*/
315		public int indexOf(Object o) {
316	<	if (o == null) {
317	<	for (int i = 0; i < size; i++)
318	<	if (elementData[i]==null)
319	<	return i;
320	<	} else {
321	<	for (int i = 0; i < size; i++)
322	<	if (o.equals(elementData[i]))
323	<	return i;
324	<	}
325	<	return -1;
316	>	if (o == null) {
317	>	for (int i = 0; i < size; i++)
318	>	if (elementData[i]==null)
319	>	return i;
320	>	} else {
321	>	for (int i = 0; i < size; i++)
322	>	if (o.equals(elementData[i]))
323	>	return i;
324	>	}
325	>	return -1;
326		}
327
328		/**
329		* Returns the index of the last occurrence of the specified element
330		* in this list, or -1 if this list does not contain the element.
331	<	* More formally, returns the highest index <tt>i</tt> such that
332	<	* <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
331	>	* More formally, returns the highest index {@code i} such that
332	>	* {@code Objects.equals(o, get(i))},
333		* or -1 if there is no such index.
334		*/
335		public int lastIndexOf(Object o) {
336	<	if (o == null) {
337	<	for (int i = size-1; i >= 0; i--)
338	<	if (elementData[i]==null)
339	<	return i;
340	<	} else {
341	<	for (int i = size-1; i >= 0; i--)
342	<	if (o.equals(elementData[i]))
343	<	return i;
344	<	}
345	<	return -1;
336	>	if (o == null) {
337	>	for (int i = size-1; i >= 0; i--)
338	>	if (elementData[i]==null)
339	>	return i;
340	>	} else {
341	>	for (int i = size-1; i >= 0; i--)
342	>	if (o.equals(elementData[i]))
343	>	return i;
344	>	}
345	>	return -1;
346		}
347
348		/**
349	<	* Returns a shallow copy of this <tt>ArrayList</tt> instance.  (The
349	>	* Returns a shallow copy of this {@code ArrayList} instance.  (The
350		* elements themselves are not copied.)
351		*
352	<	* @return a clone of this <tt>ArrayList</tt> instance
352	>	* @return a clone of this {@code ArrayList} instance
353		*/
354		public Object clone() {
355	<	try {
356	<	ArrayList<E> v = (ArrayList<E>) super.clone();
357	<	v.elementData = Arrays.copyOf(elementData, size);
358	<	v.modCount = 0;
359	<	return v;
360	<	} catch (CloneNotSupportedException e) {
361	<	// this shouldn't happen, since we are Cloneable
362	<	throw new InternalError();
363	<	}
355	>	try {
356	>	ArrayList<?> v = (ArrayList<?>) super.clone();
357	>	v.elementData = Arrays.copyOf(elementData, size);
358	>	v.modCount = 0;
359	>	return v;
360	>	} catch (CloneNotSupportedException e) {
361	>	// this shouldn't happen, since we are Cloneable
362	>	throw new InternalError(e);
363	>	}
364		}
365
366		/**
#	Line 319 | Line 392 | public class ArrayList<E> extends Abstra
392		* <p>If the list fits in the specified array with room to spare
393		* (i.e., the array has more elements than the list), the element in
394		* the array immediately following the end of the collection is set to
395	<	* <tt>null</tt>.  (This is useful in determining the length of the
395	>	* {@code null}.  (This is useful in determining the length of the
396		* list <i>only</i> if the caller knows that the list does not contain
397		* any null elements.)
398		*
#	Line 332 | Line 405 | public class ArrayList<E> extends Abstra
405		*         this list
406		* @throws NullPointerException if the specified array is null
407		*/
408	+	@SuppressWarnings("unchecked")
409		public <T> T[] toArray(T[] a) {
410		if (a.length < size)
411		// Make a new array of a's runtime type, but my contents:
412		return (T[]) Arrays.copyOf(elementData, size, a.getClass());
413	<	System.arraycopy(elementData, 0, a, 0, size);
413	>	System.arraycopy(elementData, 0, a, 0, size);
414		if (a.length > size)
415		a[size] = null;
416		return a;
#	Line 344 | Line 418 | public class ArrayList<E> extends Abstra
418
419		// Positional Access Operations
420
421	<	/**
422	<	* Returns error message string for IndexOutOfBoundsExceptions
423	<	*/
350	<	private String ioobe(int index) {
351	<	return "Index: " + index + ", Size: " + size;
421	>	@SuppressWarnings("unchecked")
422	>	E elementData(int index) {
423	>	return (E) elementData[index];
424		}
425
426		/**
#	Line 359 | Line 431 | public class ArrayList<E> extends Abstra
431		* @throws IndexOutOfBoundsException {@inheritDoc}
432		*/
433		public E get(int index) {
434	<	if (index >= size)
435	<	throw new IndexOutOfBoundsException(ioobe(index));
364	<	return (E)elementData[index];
434	>	Objects.checkIndex(index, size);
435	>	return elementData(index);
436		}
437
438		/**
#	Line 374 | Line 445 | public class ArrayList<E> extends Abstra
445		* @throws IndexOutOfBoundsException {@inheritDoc}
446		*/
447		public E set(int index, E element) {
448	<	if (index >= size)
449	<	throw new IndexOutOfBoundsException(ioobe(index));
448	>	Objects.checkIndex(index, size);
449	>	E oldValue = elementData(index);
450	>	elementData[index] = element;
451	>	return oldValue;
452	>	}
453
454	<	E oldValue = (E) elementData[index];
455	<	elementData[index] = element;
456	<	return oldValue;
454	>	/**
455	>	* This helper method split out from add(E) to keep method
456	>	* bytecode size under 35 (the -XX:MaxInlineSize default value),
457	>	* which helps when add(E) is called in a C1-compiled loop.
458	>	*/
459	>	private void add(E e, Object[] elementData, int s) {
460	>	if (s == elementData.length)
461	>	elementData = grow();
462	>	elementData[s] = e;
463	>	size = s + 1;
464		}
465
466		/**
467		* Appends the specified element to the end of this list.
468		*
469		* @param e element to be appended to this list
470	<	* @return <tt>true</tt> (as specified by {@link Collection#add})
470	>	* @return {@code true} (as specified by {@link Collection#add})
471		*/
472		public boolean add(E e) {
473		modCount++;
474	<	int s = size;
475	<	if (s >= elementData.length)
395	<	growArray(s + 1);
396	<	elementData[s] = e;
397	<	size = s + 1;
398	<	return true;
474	>	add(e, elementData, size);
475	>	return true;
476		}
477
478		/**
#	Line 408 | Line 485 | public class ArrayList<E> extends Abstra
485		* @throws IndexOutOfBoundsException {@inheritDoc}
486		*/
487		public void add(int index, E element) {
488	<	int s = size;
489	<	if (index > s || index < 0)
490	<	throw new IndexOutOfBoundsException(ioobe(index));
491	<	modCount++;
492	<	if (s >= elementData.length)
493	<	growArray(s + 1);
494	<	System.arraycopy(elementData, index,
495	<	elementData, index + 1, s - index);
496	<	elementData[index] = element;
488	>	rangeCheckForAdd(index);
489	>	modCount++;
490	>	final int s;
491	>	Object[] elementData;
492	>	if ((s = size) == (elementData = this.elementData).length)
493	>	elementData = grow();
494	>	System.arraycopy(elementData, index,
495	>	elementData, index + 1,
496	>	s - index);
497	>	elementData[index] = element;
498		size = s + 1;
499		}
500
#	Line 430 | Line 508 | public class ArrayList<E> extends Abstra
508		* @throws IndexOutOfBoundsException {@inheritDoc}
509		*/
510		public E remove(int index) {
511	<	int s = size - 1;
512	<	if (index > s)
513	<	throw new IndexOutOfBoundsException(ioobe(index));
514	<	modCount++;
515	<	E oldValue = (E)elementData[index];
516	<	int numMoved = s - index;
517	<	if (numMoved > 0)
518	<	System.arraycopy(elementData, index + 1,
519	<	elementData, index, numMoved);
520	<	elementData[s] = null;
521	<	size = s;
522	<	return oldValue;
511	>	Objects.checkIndex(index, size);
512	>
513	>	modCount++;
514	>	E oldValue = elementData(index);
515	>
516	>	int numMoved = size - index - 1;
517	>	if (numMoved > 0)
518	>	System.arraycopy(elementData, index+1, elementData, index,
519	>	numMoved);
520	>	elementData[--size] = null; // clear to let GC do its work
521	>
522	>	return oldValue;
523		}
524
525		/**
526		* Removes the first occurrence of the specified element from this list,
527		* if it is present.  If the list does not contain the element, it is
528		* unchanged.  More formally, removes the element with the lowest index
529	<	* <tt>i</tt> such that
530	<	* <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>
531	<	* (if such an element exists).  Returns <tt>true</tt> if this list
529	>	* {@code i} such that
530	>	* {@code Objects.equals(o, get(i))}
531	>	* (if such an element exists).  Returns {@code true} if this list
532		* contained the specified element (or equivalently, if this list
533		* changed as a result of the call).
534		*
535		* @param o element to be removed from this list, if present
536	<	* @return <tt>true</tt> if this list contained the specified element
536	>	* @return {@code true} if this list contained the specified element
537		*/
538		public boolean remove(Object o) {
539	<	if (o == null) {
539	>	if (o == null) {
540		for (int index = 0; index < size; index++)
541	<	if (elementData[index] == null) {
542	<	fastRemove(index);
543	<	return true;
544	<	}
545	<	} else {
546	<	for (int index = 0; index < size; index++)
547	<	if (o.equals(elementData[index])) {
548	<	fastRemove(index);
549	<	return true;
550	<	}
541	>	if (elementData[index] == null) {
542	>	fastRemove(index);
543	>	return true;
544	>	}
545	>	} else {
546	>	for (int index = 0; index < size; index++)
547	>	if (o.equals(elementData[index])) {
548	>	fastRemove(index);
549	>	return true;
550	>	}
551		}
552	<	return false;
552	>	return false;
553		}
554
555		/*
#	Line 484 | Line 562 | public class ArrayList<E> extends Abstra
562		if (numMoved > 0)
563		System.arraycopy(elementData, index+1, elementData, index,
564		numMoved);
565	<	elementData[--size] = null; // Let gc do its work
565	>	elementData[--size] = null; // clear to let GC do its work
566		}
567
568		/**
#	Line 492 | Line 570 | public class ArrayList<E> extends Abstra
570		* be empty after this call returns.
571		*/
572		public void clear() {
573	<	modCount++;
573	>	modCount++;
574
575	<	// Let gc do its work
576	<	for (int i = 0; i < size; i++)
577	<	elementData[i] = null;
575	>	// clear to let GC do its work
576	>	for (int i = 0; i < size; i++)
577	>	elementData[i] = null;
578
579	<	size = 0;
579	>	size = 0;
580		}
581
582		/**
#	Line 511 | Line 589 | public class ArrayList<E> extends Abstra
589		* list is nonempty.)
590		*
591		* @param c collection containing elements to be added to this list
592	<	* @return <tt>true</tt> if this list changed as a result of the call
592	>	* @return {@code true} if this list changed as a result of the call
593		* @throws NullPointerException if the specified collection is null
594		*/
595		public boolean addAll(Collection<? extends E> c) {
596	<	Object[] a = c.toArray();
596	>	Object[] a = c.toArray();
597	>	modCount++;
598		int numNew = a.length;
599	<	ensureCapacity(size + numNew);  // Increments modCount
600	<	System.arraycopy(a, 0, elementData, size, numNew);
601	<	size += numNew;
602	<	return numNew != 0;
599	>	if (numNew == 0)
600	>	return false;
601	>	Object[] elementData;
602	>	final int s;
603	>	if (numNew > (elementData = this.elementData).length - (s = size))
604	>	elementData = grow(s + numNew);
605	>	System.arraycopy(a, 0, elementData, s, numNew);
606	>	size = s + numNew;
607	>	return true;
608		}
609
610		/**
#	Line 534 | Line 618 | public class ArrayList<E> extends Abstra
618		* @param index index at which to insert the first element from the
619		*              specified collection
620		* @param c collection containing elements to be added to this list
621	<	* @return <tt>true</tt> if this list changed as a result of the call
621	>	* @return {@code true} if this list changed as a result of the call
622		* @throws IndexOutOfBoundsException {@inheritDoc}
623		* @throws NullPointerException if the specified collection is null
624		*/
625		public boolean addAll(int index, Collection<? extends E> c) {
626	<	if (index > size || index < 0)
543	<	throw new IndexOutOfBoundsException(ioobe(index));
626	>	rangeCheckForAdd(index);
627
628	<	Object[] a = c.toArray();
629	<	int numNew = a.length;
630	<	ensureCapacity(size + numNew);  // Increments modCount
631	<
632	<	int numMoved = size - index;
633	<	if (numMoved > 0)
634	<	System.arraycopy(elementData, index, elementData, index + numNew,
635	<	numMoved);
628	>	Object[] a = c.toArray();
629	>	modCount++;
630	>	int numNew = a.length;
631	>	if (numNew == 0)
632	>	return false;
633	>	Object[] elementData;
634	>	final int s;
635	>	if (numNew > (elementData = this.elementData).length - (s = size))
636	>	elementData = grow(s + numNew);
637
638	+	int numMoved = s - index;
639	+	if (numMoved > 0)
640	+	System.arraycopy(elementData, index,
641	+	elementData, index + numNew,
642	+	numMoved);
643		System.arraycopy(a, 0, elementData, index, numNew);
644	<	size += numNew;
645	<	return numNew != 0;
644	>	size = s + numNew;
645	>	return true;
646		}
647
648		/**
649		* Removes from this list all of the elements whose index is between
650	<	* <tt>fromIndex</tt>, inclusive, and <tt>toIndex</tt>, exclusive.
650	>	* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.
651		* Shifts any succeeding elements to the left (reduces their index).
652	<	* This call shortens the list by <tt>(toIndex - fromIndex)</tt> elements.
653	<	* (If <tt>toIndex==fromIndex</tt>, this operation has no effect.)
652	>	* This call shortens the list by {@code (toIndex - fromIndex)} elements.
653	>	* (If {@code toIndex==fromIndex}, this operation has no effect.)
654		*
655	<	* @param fromIndex index of first element to be removed
656	<	* @param toIndex index after last element to be removed
657	<	* @throws IndexOutOfBoundsException if fromIndex or toIndex out of
658	<	*              range (fromIndex &lt; 0 || fromIndex &gt;= size() || toIndex
659	<	*              &gt; size() || toIndex &lt; fromIndex)
655	>	* @throws IndexOutOfBoundsException if {@code fromIndex} or
656	>	*         {@code toIndex} is out of range
657	>	*         ({@code fromIndex < 0 ||
658	>	*          toIndex > size() ||
659	>	*          toIndex < fromIndex})
660		*/
661		protected void removeRange(int fromIndex, int toIndex) {
662	<	modCount++;
663	<	int numMoved = size - toIndex;
662	>	if (fromIndex > toIndex) {
663	>	throw new IndexOutOfBoundsException(
664	>	outOfBoundsMsg(fromIndex, toIndex));
665	>	}
666	>	modCount++;
667	>	int numMoved = size - toIndex;
668		System.arraycopy(elementData, toIndex, elementData, fromIndex,
669		numMoved);
670
671	<	// Let gc do its work
672	<	int newSize = size - (toIndex-fromIndex);
673	<	while (size != newSize)
674	<	elementData[--size] = null;
671	>	// clear to let GC do its work
672	>	int newSize = size - (toIndex-fromIndex);
673	>	for (int i = newSize; i < size; i++) {
674	>	elementData[i] = null;
675	>	}
676	>	size = newSize;
677	>	}
678	>
679	>	/**
680	>	* A version of rangeCheck used by add and addAll.
681	>	*/
682	>	private void rangeCheckForAdd(int index) {
683	>	if (index > size || index < 0)
684	>	throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
685	>	}
686	>
687	>	/**
688	>	* Constructs an IndexOutOfBoundsException detail message.
689	>	* Of the many possible refactorings of the error handling code,
690	>	* this "outlining" performs best with both server and client VMs.
691	>	*/
692	>	private String outOfBoundsMsg(int index) {
693	>	return "Index: "+index+", Size: "+size;
694	>	}
695	>
696	>	/**
697	>	* A version used in checking (fromIndex > toIndex) condition
698	>	*/
699	>	private static String outOfBoundsMsg(int fromIndex, int toIndex) {
700	>	return "From Index: " + fromIndex + " > To Index: " + toIndex;
701	>	}
702	>
703	>	/**
704	>	* Removes from this list all of its elements that are contained in the
705	>	* specified collection.
706	>	*
707	>	* @param c collection containing elements to be removed from this list
708	>	* @return {@code true} if this list changed as a result of the call
709	>	* @throws ClassCastException if the class of an element of this list
710	>	*         is incompatible with the specified collection
711	>	* (<a href="Collection.html#optional-restrictions">optional</a>)
712	>	* @throws NullPointerException if this list contains a null element and the
713	>	*         specified collection does not permit null elements
714	>	* (<a href="Collection.html#optional-restrictions">optional</a>),
715	>	*         or if the specified collection is null
716	>	* @see Collection#contains(Object)
717	>	*/
718	>	public boolean removeAll(Collection<?> c) {
719	>	Objects.requireNonNull(c);
720	>	return batchRemove(c, false);
721		}
722
723		/**
724	<	* Save the state of the <tt>ArrayList</tt> instance to a stream (that
724	>	* Retains only the elements in this list that are contained in the
725	>	* specified collection.  In other words, removes from this list all
726	>	* of its elements that are not contained in the specified collection.
727	>	*
728	>	* @param c collection containing elements to be retained in this list
729	>	* @return {@code true} if this list changed as a result of the call
730	>	* @throws ClassCastException if the class of an element of this list
731	>	*         is incompatible with the specified collection
732	>	* (<a href="Collection.html#optional-restrictions">optional</a>)
733	>	* @throws NullPointerException if this list contains a null element and the
734	>	*         specified collection does not permit null elements
735	>	* (<a href="Collection.html#optional-restrictions">optional</a>),
736	>	*         or if the specified collection is null
737	>	* @see Collection#contains(Object)
738	>	*/
739	>	public boolean retainAll(Collection<?> c) {
740	>	Objects.requireNonNull(c);
741	>	return batchRemove(c, true);
742	>	}
743	>
744	>	private boolean batchRemove(Collection<?> c, boolean complement) {
745	>	final Object[] elementData = this.elementData;
746	>	int r = 0, w = 0;
747	>	boolean modified = false;
748	>	try {
749	>	for (; r < size; r++)
750	>	if (c.contains(elementData[r]) == complement)
751	>	elementData[w++] = elementData[r];
752	>	} finally {
753	>	// Preserve behavioral compatibility with AbstractCollection,
754	>	// even if c.contains() throws.
755	>	if (r != size) {
756	>	System.arraycopy(elementData, r,
757	>	elementData, w,
758	>	size - r);
759	>	w += size - r;
760	>	}
761	>	if (w != size) {
762	>	// clear to let GC do its work
763	>	for (int i = w; i < size; i++)
764	>	elementData[i] = null;
765	>	modCount += size - w;
766	>	size = w;
767	>	modified = true;
768	>	}
769	>	}
770	>	return modified;
771	>	}
772	>
773	>	/**
774	>	* Save the state of the {@code ArrayList} instance to a stream (that
775		* is, serialize it).
776		*
777	<	* @serialData The length of the array backing the <tt>ArrayList</tt>
777	>	* @serialData The length of the array backing the {@code ArrayList}
778		*             instance is emitted (int), followed by all of its elements
779	<	*             (each an <tt>Object</tt>) in the proper order.
779	>	*             (each an {@code Object}) in the proper order.
780		*/
781		private void writeObject(java.io.ObjectOutputStream s)
782		throws java.io.IOException{
783	<	// Write out element count, and any hidden stuff
784	<	int expectedModCount = modCount;
785	<	s.defaultWriteObject();
783	>	// Write out element count, and any hidden stuff
784	>	int expectedModCount = modCount;
785	>	s.defaultWriteObject();
786
787	<	// Write out array length
788	<	s.writeInt(elementData.length);
787	>	// Write out size as capacity for behavioural compatibility with clone()
788	>	s.writeInt(size);
789
790	<	// Write out all elements in the proper order.
791	<	for (int i=0; i<size; i++)
790	>	// Write out all elements in the proper order.
791	>	for (int i=0; i<size; i++) {
792		s.writeObject(elementData[i]);
793	+	}
794
795	<	if (expectedModCount != modCount) {
795	>	if (modCount != expectedModCount) {
796		throw new ConcurrentModificationException();
797		}
608	–
798		}
799
800		/**
801	<	* Reconstitute the <tt>ArrayList</tt> instance from a stream (that is,
801	>	* Reconstitute the {@code ArrayList} instance from a stream (that is,
802		* deserialize it).
803		*/
804		private void readObject(java.io.ObjectInputStream s)
805		throws java.io.IOException, ClassNotFoundException {
617	–	// Read in size, and any hidden stuff
618	–	s.defaultReadObject();
806
807	<	// Read in array length and allocate array
808	<	int arrayLength = s.readInt();
622	<	Object[] a = elementData = new Object[arrayLength];
807	>	// Read in size, and any hidden stuff
808	>	s.defaultReadObject();
809
810	<	// Read in all elements in the proper order.
811	<	for (int i=0; i<size; i++)
626	<	a[i] = s.readObject();
627	<	}
810	>	// Read in capacity
811	>	s.readInt(); // ignored
812
813	+	if (size > 0) {
814	+	// like clone(), allocate array based upon size not capacity
815	+	Object[] elements = new Object[size];
816	+
817	+	// Read in all elements in the proper order.
818	+	for (int i = 0; i < size; i++) {
819	+	elements[i] = s.readObject();
820	+	}
821	+
822	+	elementData = elements;
823	+	} else if (size == 0) {
824	+	elementData = EMPTY_ELEMENTDATA;
825	+	} else {
826	+	throw new java.io.InvalidObjectException("Invalid size: " + size);
827	+	}
828	+	}
829
830		/**
831	<	* Returns a list-iterator of the elements in this list (in proper
831	>	* Returns a list iterator over the elements in this list (in proper
832		* sequence), starting at the specified position in the list.
833	<	* Obeys the general contract of <tt>List.listIterator(int)</tt>.<p>
833	>	* The specified index indicates the first element that would be
834	>	* returned by an initial call to {@link ListIterator#next next}.
835	>	* An initial call to {@link ListIterator#previous previous} would
836	>	* return the element with the specified index minus one.
837	>	*
838	>	* <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
839		*
635	–	* The list-iterator is <i>fail-fast</i>: if the list is structurally
636	–	* modified at any time after the Iterator is created, in any way except
637	–	* through the list-iterator's own <tt>remove</tt> or <tt>add</tt>
638	–	* methods, the list-iterator will throw a
639	–	* <tt>ConcurrentModificationException</tt>.  Thus, in the face of
640	–	* concurrent modification, the iterator fails quickly and cleanly, rather
641	–	* than risking arbitrary, non-deterministic behavior at an undetermined
642	–	* time in the future.
643	–	*
644	–	* @param index index of the first element to be returned from the
645	–	*              list-iterator (by a call to <tt>next</tt>)
646	–	* @return a ListIterator of the elements in this list (in proper
647	–	*         sequence), starting at the specified position in the list
840		* @throws IndexOutOfBoundsException {@inheritDoc}
649	–	* @see List#listIterator(int)
841		*/
842		public ListIterator<E> listIterator(int index) {
843	<	if (index < 0 || index > size)
844	<	throw new IndexOutOfBoundsException(ioobe(index));
654	<	return new ArrayListIterator(index);
843	>	rangeCheckForAdd(index);
844	>	return new ListItr(index);
845		}
846
847		/**
848	<	* {@inheritDoc}
848	>	* Returns a list iterator over the elements in this list (in proper
849	>	* sequence).
850	>	*
851	>	* <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
852	>	*
853	>	* @see #listIterator(int)
854		*/
855		public ListIterator<E> listIterator() {
856	<	return new ArrayListIterator(0);
856	>	return new ListItr(0);
857		}
858
859		/**
860		* Returns an iterator over the elements in this list in proper sequence.
861		*
862	+	* <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
863	+	*
864		* @return an iterator over the elements in this list in proper sequence
865		*/
866		public Iterator<E> iterator() {
867	<	return new ArrayListIterator(0);
867	>	return new Itr();
868		}
869
870		/**
871	<	* A streamlined version of AbstractList.ListItr
871	>	* An optimized version of AbstractList.Itr
872		*/
873	<	final class ArrayListIterator implements ListIterator<E> {
874	<	int cursor;           // index of next element to return;
875	<	int lastRet;          // index of last element, or -1 if no such
876	<	int expectedModCount; // to check for CME
680	<
681	<	ArrayListIterator(int index) {
682	<	cursor = index;
683	<	lastRet = -1;
684	<	expectedModCount = modCount;
685	<	}
873	>	private class Itr implements Iterator<E> {
874	>	int cursor;       // index of next element to return
875	>	int lastRet = -1; // index of last element returned; -1 if no such
876	>	int expectedModCount = modCount;
877
878	<	public boolean hasNext() {
879	<	return cursor < size;
689	<	}
878	>	// prevent creating a synthetic constructor
879	>	Itr() {}
880
881	<	public boolean hasPrevious() {
882	<	return cursor > 0;
883	<	}
881	>	public boolean hasNext() {
882	>	return cursor != size;
883	>	}
884
885	<	public int nextIndex() {
886	<	return cursor;
887	<	}
885	>	@SuppressWarnings("unchecked")
886	>	public E next() {
887	>	checkForComodification();
888	>	int i = cursor;
889	>	if (i >= size)
890	>	throw new NoSuchElementException();
891	>	Object[] elementData = ArrayList.this.elementData;
892	>	if (i >= elementData.length)
893	>	throw new ConcurrentModificationException();
894	>	cursor = i + 1;
895	>	return (E) elementData[lastRet = i];
896	>	}
897
898	<	public int previousIndex() {
899	<	return cursor - 1;
900	<	}
898	>	public void remove() {
899	>	if (lastRet < 0)
900	>	throw new IllegalStateException();
901	>	checkForComodification();
902
703	–	public E next() {
903		try {
904	<	int i = cursor;
905	<	E next = get(i);
906	<	lastRet = i;
907	<	cursor = i + 1;
709	<	return next;
904	>	ArrayList.this.remove(lastRet);
905	>	cursor = lastRet;
906	>	lastRet = -1;
907	>	expectedModCount = modCount;
908		} catch (IndexOutOfBoundsException ex) {
909	<	throw new NoSuchElementException();
712	<	} finally {
713	<	if (expectedModCount != modCount)
714	<	throw new ConcurrentModificationException();
909	>	throw new ConcurrentModificationException();
910		}
911	<	}
911	>	}
912
913	+	@Override
914	+	@SuppressWarnings("unchecked")
915	+	public void forEachRemaining(Consumer<? super E> consumer) {
916	+	Objects.requireNonNull(consumer);
917	+	final int size = ArrayList.this.size;
918	+	int i = cursor;
919	+	if (i >= size) {
920	+	return;
921	+	}
922	+	final Object[] elementData = ArrayList.this.elementData;
923	+	if (i >= elementData.length) {
924	+	throw new ConcurrentModificationException();
925	+	}
926	+	while (i != size && modCount == expectedModCount) {
927	+	consumer.accept((E) elementData[i++]);
928	+	}
929	+	// update once at end of iteration to reduce heap write traffic
930	+	cursor = i;
931	+	lastRet = i - 1;
932	+	checkForComodification();
933	+	}
934	+
935	+	final void checkForComodification() {
936	+	if (modCount != expectedModCount)
937	+	throw new ConcurrentModificationException();
938	+	}
939	+	}
940	+
941	+	/**
942	+	* An optimized version of AbstractList.ListItr
943	+	*/
944	+	private class ListItr extends Itr implements ListIterator<E> {
945	+	ListItr(int index) {
946	+	super();
947	+	cursor = index;
948	+	}
949	+
950	+	public boolean hasPrevious() {
951	+	return cursor != 0;
952	+	}
953	+
954	+	public int nextIndex() {
955	+	return cursor;
956	+	}
957	+
958	+	public int previousIndex() {
959	+	return cursor - 1;
960	+	}
961	+
962	+	@SuppressWarnings("unchecked")
963		public E previous() {
964	+	checkForComodification();
965	+	int i = cursor - 1;
966	+	if (i < 0)
967	+	throw new NoSuchElementException();
968	+	Object[] elementData = ArrayList.this.elementData;
969	+	if (i >= elementData.length)
970	+	throw new ConcurrentModificationException();
971	+	cursor = i;
972	+	return (E) elementData[lastRet = i];
973	+	}
974	+
975	+	public void set(E e) {
976	+	if (lastRet < 0)
977	+	throw new IllegalStateException();
978	+	checkForComodification();
979	+
980		try {
981	<	int i = cursor - 1;
721	<	E prev = get(i);
722	<	lastRet = i;
723	<	cursor = i;
724	<	return prev;
981	>	ArrayList.this.set(lastRet, e);
982		} catch (IndexOutOfBoundsException ex) {
983	<	throw new NoSuchElementException();
727	<	} finally {
728	<	if (expectedModCount != modCount)
729	<	throw new ConcurrentModificationException();
983	>	throw new ConcurrentModificationException();
984		}
985		}
986
987	<	public void remove() {
988	<	if (lastRet < 0)
989	<	throw new IllegalStateException();
990	<	if (expectedModCount != modCount)
991	<	throw new ConcurrentModificationException();
992	<	ArrayList.this.remove(lastRet);
993	<	if (lastRet < cursor)
994	<	cursor--;
995	<	lastRet = -1;
996	<	expectedModCount = modCount;
743	<	}
744	<
745	<	public void set(E e) {
746	<	if (lastRet < 0)
747	<	throw new IllegalStateException();
748	<	if (expectedModCount != modCount)
987	>	public void add(E e) {
988	>	checkForComodification();
989	>
990	>	try {
991	>	int i = cursor;
992	>	ArrayList.this.add(i, e);
993	>	cursor = i + 1;
994	>	lastRet = -1;
995	>	expectedModCount = modCount;
996	>	} catch (IndexOutOfBoundsException ex) {
997		throw new ConcurrentModificationException();
998	<	ArrayList.this.set(lastRet, e);
999	<	expectedModCount = modCount;
1000	<	}
998	>	}
999	>	}
1000	>	}
1001	>
1002	>	/**
1003	>	* Returns a view of the portion of this list between the specified
1004	>	* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.  (If
1005	>	* {@code fromIndex} and {@code toIndex} are equal, the returned list is
1006	>	* empty.)  The returned list is backed by this list, so non-structural
1007	>	* changes in the returned list are reflected in this list, and vice-versa.
1008	>	* The returned list supports all of the optional list operations.
1009	>	*
1010	>	* <p>This method eliminates the need for explicit range operations (of
1011	>	* the sort that commonly exist for arrays).  Any operation that expects
1012	>	* a list can be used as a range operation by passing a subList view
1013	>	* instead of a whole list.  For example, the following idiom
1014	>	* removes a range of elements from a list:
1015	>	* <pre>
1016	>	*      list.subList(from, to).clear();
1017	>	* </pre>
1018	>	* Similar idioms may be constructed for {@link #indexOf(Object)} and
1019	>	* {@link #lastIndexOf(Object)}, and all of the algorithms in the
1020	>	* {@link Collections} class can be applied to a subList.
1021	>	*
1022	>	* <p>The semantics of the list returned by this method become undefined if
1023	>	* the backing list (i.e., this list) is <i>structurally modified</i> in
1024	>	* any way other than via the returned list.  (Structural modifications are
1025	>	* those that change the size of this list, or otherwise perturb it in such
1026	>	* a fashion that iterations in progress may yield incorrect results.)
1027	>	*
1028	>	* @throws IndexOutOfBoundsException {@inheritDoc}
1029	>	* @throws IllegalArgumentException {@inheritDoc}
1030	>	*/
1031	>	public List<E> subList(int fromIndex, int toIndex) {
1032	>	subListRangeCheck(fromIndex, toIndex, size);
1033	>	return new SubList<>(this, fromIndex, toIndex);
1034	>	}
1035	>
1036	>	private static class SubList<E> extends AbstractList<E> implements RandomAccess {
1037	>	private final ArrayList<E> root;
1038	>	private final SubList<E> parent;
1039	>	private final int offset;
1040	>	private int size;
1041	>
1042	>	/**
1043	>	* Constructs a sublist of an arbitrary ArrayList.
1044	>	*/
1045	>	public SubList(ArrayList<E> root, int fromIndex, int toIndex) {
1046	>	this.root = root;
1047	>	this.parent = null;
1048	>	this.offset = fromIndex;
1049	>	this.size = toIndex - fromIndex;
1050	>	this.modCount = root.modCount;
1051	>	}
1052
1053	<	public void add(E e) {
1054	<	if (expectedModCount != modCount)
1053	>	/**
1054	>	* Constructs a sublist of another SubList.
1055	>	*/
1056	>	private SubList(SubList<E> parent, int fromIndex, int toIndex) {
1057	>	this.root = parent.root;
1058	>	this.parent = parent;
1059	>	this.offset = parent.offset + fromIndex;
1060	>	this.size = toIndex - fromIndex;
1061	>	this.modCount = root.modCount;
1062	>	}
1063	>
1064	>	public E set(int index, E element) {
1065	>	Objects.checkIndex(index, size);
1066	>	checkForComodification();
1067	>	E oldValue = root.elementData(offset + index);
1068	>	root.elementData[offset + index] = element;
1069	>	return oldValue;
1070	>	}
1071	>
1072	>	public E get(int index) {
1073	>	Objects.checkIndex(index, size);
1074	>	checkForComodification();
1075	>	return root.elementData(offset + index);
1076	>	}
1077	>
1078	>	public int size() {
1079	>	checkForComodification();
1080	>	return size;
1081	>	}
1082	>
1083	>	public void add(int index, E element) {
1084	>	rangeCheckForAdd(index);
1085	>	checkForComodification();
1086	>	root.add(offset + index, element);
1087	>	updateSizeAndModCount(1);
1088	>	}
1089	>
1090	>	public E remove(int index) {
1091	>	Objects.checkIndex(index, size);
1092	>	checkForComodification();
1093	>	E result = root.remove(offset + index);
1094	>	updateSizeAndModCount(-1);
1095	>	return result;
1096	>	}
1097	>
1098	>	protected void removeRange(int fromIndex, int toIndex) {
1099	>	checkForComodification();
1100	>	root.removeRange(offset + fromIndex, offset + toIndex);
1101	>	updateSizeAndModCount(fromIndex - toIndex);
1102	>	}
1103	>
1104	>	public boolean addAll(Collection<? extends E> c) {
1105	>	return addAll(this.size, c);
1106	>	}
1107	>
1108	>	public boolean addAll(int index, Collection<? extends E> c) {
1109	>	rangeCheckForAdd(index);
1110	>	int cSize = c.size();
1111	>	if (cSize==0)
1112	>	return false;
1113	>	checkForComodification();
1114	>	root.addAll(offset + index, c);
1115	>	updateSizeAndModCount(cSize);
1116	>	return true;
1117	>	}
1118	>
1119	>	public Iterator<E> iterator() {
1120	>	return listIterator();
1121	>	}
1122	>
1123	>	public ListIterator<E> listIterator(int index) {
1124	>	checkForComodification();
1125	>	rangeCheckForAdd(index);
1126	>
1127	>	return new ListIterator<E>() {
1128	>	int cursor = index;
1129	>	int lastRet = -1;
1130	>	int expectedModCount = root.modCount;
1131	>
1132	>	public boolean hasNext() {
1133	>	return cursor != SubList.this.size;
1134	>	}
1135	>
1136	>	@SuppressWarnings("unchecked")
1137	>	public E next() {
1138	>	checkForComodification();
1139	>	int i = cursor;
1140	>	if (i >= SubList.this.size)
1141	>	throw new NoSuchElementException();
1142	>	Object[] elementData = root.elementData;
1143	>	if (offset + i >= elementData.length)
1144	>	throw new ConcurrentModificationException();
1145	>	cursor = i + 1;
1146	>	return (E) elementData[offset + (lastRet = i)];
1147	>	}
1148	>
1149	>	public boolean hasPrevious() {
1150	>	return cursor != 0;
1151	>	}
1152	>
1153	>	@SuppressWarnings("unchecked")
1154	>	public E previous() {
1155	>	checkForComodification();
1156	>	int i = cursor - 1;
1157	>	if (i < 0)
1158	>	throw new NoSuchElementException();
1159	>	Object[] elementData = root.elementData;
1160	>	if (offset + i >= elementData.length)
1161	>	throw new ConcurrentModificationException();
1162	>	cursor = i;
1163	>	return (E) elementData[offset + (lastRet = i)];
1164	>	}
1165	>
1166	>	@SuppressWarnings("unchecked")
1167	>	public void forEachRemaining(Consumer<? super E> consumer) {
1168	>	Objects.requireNonNull(consumer);
1169	>	final int size = SubList.this.size;
1170	>	int i = cursor;
1171	>	if (i >= size) {
1172	>	return;
1173	>	}
1174	>	final Object[] elementData = root.elementData;
1175	>	if (offset + i >= elementData.length) {
1176	>	throw new ConcurrentModificationException();
1177	>	}
1178	>	while (i != size && modCount == expectedModCount) {
1179	>	consumer.accept((E) elementData[offset + (i++)]);
1180	>	}
1181	>	// update once at end of iteration to reduce heap write traffic
1182	>	lastRet = cursor = i;
1183	>	checkForComodification();
1184	>	}
1185	>
1186	>	public int nextIndex() {
1187	>	return cursor;
1188	>	}
1189	>
1190	>	public int previousIndex() {
1191	>	return cursor - 1;
1192	>	}
1193	>
1194	>	public void remove() {
1195	>	if (lastRet < 0)
1196	>	throw new IllegalStateException();
1197	>	checkForComodification();
1198	>
1199	>	try {
1200	>	SubList.this.remove(lastRet);
1201	>	cursor = lastRet;
1202	>	lastRet = -1;
1203	>	expectedModCount = root.modCount;
1204	>	} catch (IndexOutOfBoundsException ex) {
1205	>	throw new ConcurrentModificationException();
1206	>	}
1207	>	}
1208	>
1209	>	public void set(E e) {
1210	>	if (lastRet < 0)
1211	>	throw new IllegalStateException();
1212	>	checkForComodification();
1213	>
1214	>	try {
1215	>	root.set(offset + lastRet, e);
1216	>	} catch (IndexOutOfBoundsException ex) {
1217	>	throw new ConcurrentModificationException();
1218	>	}
1219	>	}
1220	>
1221	>	public void add(E e) {
1222	>	checkForComodification();
1223	>
1224	>	try {
1225	>	int i = cursor;
1226	>	SubList.this.add(i, e);
1227	>	cursor = i + 1;
1228	>	lastRet = -1;
1229	>	expectedModCount = root.modCount;
1230	>	} catch (IndexOutOfBoundsException ex) {
1231	>	throw new ConcurrentModificationException();
1232	>	}
1233	>	}
1234	>
1235	>	final void checkForComodification() {
1236	>	if (root.modCount != expectedModCount)
1237	>	throw new ConcurrentModificationException();
1238	>	}
1239	>	};
1240	>	}
1241	>
1242	>	public List<E> subList(int fromIndex, int toIndex) {
1243	>	subListRangeCheck(fromIndex, toIndex, size);
1244	>	return new SubList<>(this, fromIndex, toIndex);
1245	>	}
1246	>
1247	>	private void rangeCheckForAdd(int index) {
1248	>	if (index < 0 || index > this.size)
1249	>	throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
1250	>	}
1251	>
1252	>	private String outOfBoundsMsg(int index) {
1253	>	return "Index: "+index+", Size: "+this.size;
1254	>	}
1255	>
1256	>	private void checkForComodification() {
1257	>	if (root.modCount != modCount)
1258		throw new ConcurrentModificationException();
1259	<	ArrayList.this.add(cursor++, e);
1260	<	lastRet = -1;
1261	<	expectedModCount = modCount;
1262	<	}
1259	>	}
1260	>
1261	>	private void updateSizeAndModCount(int sizeChange) {
1262	>	SubList<E> slist = this;
1263	>	do {
1264	>	slist.size += sizeChange;
1265	>	slist.modCount = root.modCount;
1266	>	slist = slist.parent;
1267	>	} while (slist != null);
1268	>	}
1269	>
1270	>	public Spliterator<E> spliterator() {
1271	>	checkForComodification();
1272	>
1273	>	// ArrayListSpliterator is not used because late-binding logic
1274	>	// is different here
1275	>	return new Spliterator<>() {
1276	>	private int index = offset; // current index, modified on advance/split
1277	>	private int fence = -1; // -1 until used; then one past last index
1278	>	private int expectedModCount; // initialized when fence set
1279	>
1280	>	private int getFence() { // initialize fence to size on first use
1281	>	int hi; // (a specialized variant appears in method forEach)
1282	>	if ((hi = fence) < 0) {
1283	>	expectedModCount = modCount;
1284	>	hi = fence = offset + size;
1285	>	}
1286	>	return hi;
1287	>	}
1288	>
1289	>	public ArrayListSpliterator<E> trySplit() {
1290	>	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1291	>	// ArrayListSpliterator could be used here as the source is already bound
1292	>	return (lo >= mid) ? null : // divide range in half unless too small
1293	>	new ArrayListSpliterator<>(root, lo, index = mid,
1294	>	expectedModCount);
1295	>	}
1296	>
1297	>	public boolean tryAdvance(Consumer<? super E> action) {
1298	>	Objects.requireNonNull(action);
1299	>	int hi = getFence(), i = index;
1300	>	if (i < hi) {
1301	>	index = i + 1;
1302	>	@SuppressWarnings("unchecked") E e = (E)root.elementData[i];
1303	>	action.accept(e);
1304	>	if (root.modCount != expectedModCount)
1305	>	throw new ConcurrentModificationException();
1306	>	return true;
1307	>	}
1308	>	return false;
1309	>	}
1310	>
1311	>	public void forEachRemaining(Consumer<? super E> action) {
1312	>	Objects.requireNonNull(action);
1313	>	int i, hi, mc; // hoist accesses and checks from loop
1314	>	ArrayList<E> lst = root;
1315	>	Object[] a;
1316	>	if ((a = lst.elementData) != null) {
1317	>	if ((hi = fence) < 0) {
1318	>	mc = modCount;
1319	>	hi = offset + size;
1320	>	}
1321	>	else
1322	>	mc = expectedModCount;
1323	>	if ((i = index) >= 0 && (index = hi) <= a.length) {
1324	>	for (; i < hi; ++i) {
1325	>	@SuppressWarnings("unchecked") E e = (E) a[i];
1326	>	action.accept(e);
1327	>	}
1328	>	if (lst.modCount == mc)
1329	>	return;
1330	>	}
1331	>	}
1332	>	throw new ConcurrentModificationException();
1333	>	}
1334	>
1335	>	public long estimateSize() {
1336	>	return (long) (getFence() - index);
1337	>	}
1338	>
1339	>	public int characteristics() {
1340	>	return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
1341	>	}
1342	>	};
1343	>	}
1344	>	}
1345	>
1346	>	@Override
1347	>	public void forEach(Consumer<? super E> action) {
1348	>	Objects.requireNonNull(action);
1349	>	final int expectedModCount = modCount;
1350	>	@SuppressWarnings("unchecked")
1351	>	final E[] elementData = (E[]) this.elementData;
1352	>	final int size = this.size;
1353	>	for (int i=0; modCount == expectedModCount && i < size; i++) {
1354	>	action.accept(elementData[i]);
1355	>	}
1356	>	if (modCount != expectedModCount) {
1357	>	throw new ConcurrentModificationException();
1358	>	}
1359	>	}
1360	>
1361	>	/**
1362	>	* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
1363	>	* and <em>fail-fast</em> {@link Spliterator} over the elements in this
1364	>	* list.
1365	>	*
1366	>	* <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
1367	>	* {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}.
1368	>	* Overriding implementations should document the reporting of additional
1369	>	* characteristic values.
1370	>	*
1371	>	* @return a {@code Spliterator} over the elements in this list
1372	>	* @since 1.8
1373	>	*/
1374	>	@Override
1375	>	public Spliterator<E> spliterator() {
1376	>	return new ArrayListSpliterator<>(this, 0, -1, 0);
1377	>	}
1378	>
1379	>	/** Index-based split-by-two, lazily initialized Spliterator */
1380	>	static final class ArrayListSpliterator<E> implements Spliterator<E> {
1381	>
1382	>	/*
1383	>	* If ArrayLists were immutable, or structurally immutable (no
1384	>	* adds, removes, etc), we could implement their spliterators
1385	>	* with Arrays.spliterator. Instead we detect as much
1386	>	* interference during traversal as practical without
1387	>	* sacrificing much performance. We rely primarily on
1388	>	* modCounts. These are not guaranteed to detect concurrency
1389	>	* violations, and are sometimes overly conservative about
1390	>	* within-thread interference, but detect enough problems to
1391	>	* be worthwhile in practice. To carry this out, we (1) lazily
1392	>	* initialize fence and expectedModCount until the latest
1393	>	* point that we need to commit to the state we are checking
1394	>	* against; thus improving precision.  (This doesn't apply to
1395	>	* SubLists, that create spliterators with current non-lazy
1396	>	* values).  (2) We perform only a single
1397	>	* ConcurrentModificationException check at the end of forEach
1398	>	* (the most performance-sensitive method). When using forEach
1399	>	* (as opposed to iterators), we can normally only detect
1400	>	* interference after actions, not before. Further
1401	>	* CME-triggering checks apply to all other possible
1402	>	* violations of assumptions for example null or too-small
1403	>	* elementData array given its size(), that could only have
1404	>	* occurred due to interference.  This allows the inner loop
1405	>	* of forEach to run without any further checks, and
1406	>	* simplifies lambda-resolution. While this does entail a
1407	>	* number of checks, note that in the common case of
1408	>	* list.stream().forEach(a), no checks or other computation
1409	>	* occur anywhere other than inside forEach itself.  The other
1410	>	* less-often-used methods cannot take advantage of most of
1411	>	* these streamlinings.
1412	>	*/
1413	>
1414	>	private final ArrayList<E> list;
1415	>	private int index; // current index, modified on advance/split
1416	>	private int fence; // -1 until used; then one past last index
1417	>	private int expectedModCount; // initialized when fence set
1418	>
1419	>	/** Create new spliterator covering the given  range */
1420	>	ArrayListSpliterator(ArrayList<E> list, int origin, int fence,
1421	>	int expectedModCount) {
1422	>	this.list = list; // OK if null unless traversed
1423	>	this.index = origin;
1424	>	this.fence = fence;
1425	>	this.expectedModCount = expectedModCount;
1426	>	}
1427	>
1428	>	private int getFence() { // initialize fence to size on first use
1429	>	int hi; // (a specialized variant appears in method forEach)
1430	>	ArrayList<E> lst;
1431	>	if ((hi = fence) < 0) {
1432	>	if ((lst = list) == null)
1433	>	hi = fence = 0;
1434	>	else {
1435	>	expectedModCount = lst.modCount;
1436	>	hi = fence = lst.size;
1437	>	}
1438	>	}
1439	>	return hi;
1440	>	}
1441	>
1442	>	public ArrayListSpliterator<E> trySplit() {
1443	>	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1444	>	return (lo >= mid) ? null : // divide range in half unless too small
1445	>	new ArrayListSpliterator<>(list, lo, index = mid,
1446	>	expectedModCount);
1447	>	}
1448	>
1449	>	public boolean tryAdvance(Consumer<? super E> action) {
1450	>	if (action == null)
1451	>	throw new NullPointerException();
1452	>	int hi = getFence(), i = index;
1453	>	if (i < hi) {
1454	>	index = i + 1;
1455	>	@SuppressWarnings("unchecked") E e = (E)list.elementData[i];
1456	>	action.accept(e);
1457	>	if (list.modCount != expectedModCount)
1458	>	throw new ConcurrentModificationException();
1459	>	return true;
1460	>	}
1461	>	return false;
1462	>	}
1463	>
1464	>	public void forEachRemaining(Consumer<? super E> action) {
1465	>	int i, hi, mc; // hoist accesses and checks from loop
1466	>	ArrayList<E> lst; Object[] a;
1467	>	if (action == null)
1468	>	throw new NullPointerException();
1469	>	if ((lst = list) != null && (a = lst.elementData) != null) {
1470	>	if ((hi = fence) < 0) {
1471	>	mc = lst.modCount;
1472	>	hi = lst.size;
1473	>	}
1474	>	else
1475	>	mc = expectedModCount;
1476	>	if ((i = index) >= 0 && (index = hi) <= a.length) {
1477	>	for (; i < hi; ++i) {
1478	>	@SuppressWarnings("unchecked") E e = (E) a[i];
1479	>	action.accept(e);
1480	>	}
1481	>	if (lst.modCount == mc)
1482	>	return;
1483	>	}
1484	>	}
1485	>	throw new ConcurrentModificationException();
1486	>	}
1487	>
1488	>	public long estimateSize() {
1489	>	return (long) (getFence() - index);
1490	>	}
1491	>
1492	>	public int characteristics() {
1493	>	return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
1494	>	}
1495	>	}
1496	>
1497	>	@SuppressWarnings("unchecked")
1498	>	@Override
1499	>	public boolean removeIf(Predicate<? super E> filter) {
1500	>	Objects.requireNonNull(filter);
1501	>	int expectedModCount = modCount;
1502	>	final Object[] es = elementData;
1503	>	final int size = this.size;
1504	>	final boolean modified;
1505	>	int r;
1506	>	for (r = 0; r < size; r++)
1507	>	if (filter.test((E) es[r]))
1508	>	break;
1509	>	if (modified = (r < size)) {
1510	>	expectedModCount++;
1511	>	modCount++;
1512	>	int w = r++;
1513	>	try {
1514	>	for (E e; r < size; r++)
1515	>	if (!filter.test(e = (E) es[r]))
1516	>	es[w++] = e;
1517	>	Arrays.fill(es, (this.size = w), size, null);
1518	>	} catch (Throwable ex) {
1519	>	// copy remaining elements
1520	>	System.arraycopy(es, r, es, w, size - r);
1521	>	Arrays.fill(es, (this.size = w + size - r), size, null);
1522	>	throw ex;
1523	>	}
1524	>	}
1525	>	if (modCount != expectedModCount)
1526	>	throw new ConcurrentModificationException();
1527	>	return modified;
1528	>	}
1529	>
1530	>	@Override
1531	>	@SuppressWarnings("unchecked")
1532	>	public void replaceAll(UnaryOperator<E> operator) {
1533	>	Objects.requireNonNull(operator);
1534	>	final int expectedModCount = modCount;
1535	>	final int size = this.size;
1536	>	for (int i=0; modCount == expectedModCount && i < size; i++) {
1537	>	elementData[i] = operator.apply((E) elementData[i]);
1538	>	}
1539	>	if (modCount != expectedModCount) {
1540	>	throw new ConcurrentModificationException();
1541	>	}
1542	>	modCount++;
1543	>	}
1544	>
1545	>	@Override
1546	>	@SuppressWarnings("unchecked")
1547	>	public void sort(Comparator<? super E> c) {
1548	>	final int expectedModCount = modCount;
1549	>	Arrays.sort((E[]) elementData, 0, size, c);
1550	>	if (modCount != expectedModCount) {
1551	>	throw new ConcurrentModificationException();
1552	>	}
1553	>	modCount++;
1554		}
1555		}

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